Work vehicles often include, as in the case of construction equipment (e.g., front end loaders and backhoes), attached implements such as buckets for tasks such as excavating soil. Such implements include actuators, often in the form of hydraulic cylinders, which are controlled by operator commands transmitted to an implement position control system by using operator manual input devices such as levers, joysticks, pedals, knobs or the like.
A work vehicle is generally provided with an operator station having a seat located for good visibility of the work being done by the implement and for best access to the operator input devices. To preclude operation of the implement with an operator not properly positioned at the operator input devices, an operator presence sensor may be provided in the form of a seat switch; i.e., a switch located within or under the seat and disposed to change state when the operator is seated and his weight is borne by the seat. Actuation of the seat switch upon seating of the operator typically provides a signal to an implement control system which enables response of the actuators to operator commands, while rising of the operator from the seat disables at least a portion of the implement by causing a least a portion of the control system to no longer respond to operator commands and to instead cause the portion of the implement to remain in the position it was disposed in upon the rising of the operator from the seat.
In some cases, however, an operator may prefer to briefly stand at the operator input devices so that, while remaining in a position suitable for manipulating the operator input devices, he may obtain a better view of work in progress; e.g., excavating of a deep trench with a backhoe. He is not able to do so, however, if a presence sensor such as a seat switch will disable actuator response to his implement position commands.
It would be advantageous to provide for a work vehicle having an implement including actuators, an operator's seat in the region of operator input devices, and an implement position control system including an implement disabling circuit associated with the seat, to include an override device for allowing continuing enablement of the operator input devices for so long as the operator remains engaged with the override device regardless of the operator's position with respect to the seat.
It would also be advantageous to provide for such an override device to be in the general nature of a momentary contact switch affixed to at least one of the operator input devices, the control system configured for engagement of the momentary contact switch to have effect when engaged by the operator prior to his rising from the seat.